The present invention relates to hybrid microcircuits, and more particularly, to a glass-to-metal seal repair process for use with in repairing hybrid microcircuit headers having leaking seals.
Heretofore there has been no approved method for repairing leaking glass-to-metal seals of hybrid microcircuits used on Government programs, that insures their reliability once they are placed in operation. When leaks are encountered, two options have typically been available. The most common option is to scrap the hybrid microcircuit. The second option is to shear the ceramic substrate from its faulty header and rebond it into a new header. The header is the portion of the microcircuit containing the glass-to-metal seals. However, this process is very labor intensive and is operator dependent.. This method of repair often results in scrap caused by damaged substrates during the shearing process.
The following patents generally relate to methods or apparatus for repairing glass seals or encapsulates for hybrid microcircuits where silicon resins are applied to the leaks in the glass seals in a vacuum environment. Japanese 66-44742 assigned to Hitachi Ltd. discloses that in a vacuum chamber, a thin film of disilane is deposited at a localized defect in a circuit. U.S. Pat. No. 4,466,992 issued to Dreiling discloses that in a vacuum chamber, pinhole defects in a substrate semiconductor film are filled with heated silane or silicon compounds, and at column 3, lines 6-9 it is disclosed that substrates such as quartz, glass, and transparent polymeric materials can be repaired.
U.S. Pat. No. 4,508,758 issued to Wong discloses that in manufacturing encapsulated hybrid circuits, a first compound (RTV silicon) is used to form a wall around the periphery of each circuit and second encapsulate (polydimethyl siloxane) is flow coated over the the circuit within the wall formed by the first compound. In column 4, lines 10-15 it is disclosed that the encapsulate may be applied by hand or by use of a syringe. U.S. Pat. No. 4,708,889 issued to Hammond discloses that liquid silicates that are liquid at temperatures below the melting point of glass are used to repair glass and ceramic seals.
U.S. Pat. No. 5,156,853 issued to Werner discloses that windshield cracks may be repaired by applying a vacuum to the region adjacent to the crack and filling the crack with a liquid resin. U.S. Pat. No. 5,302,237 issued to Larson discloses that a plasma vacuum unit may be used for localized etching or depositions.
However, none of the above-cited patents disclose a glass-to-metal seal repair process for use with hybrid microcircuits as is provided for in the present invention.
Therefore, it is an objective of the present invention to provide for an improved glass-to-metal seal repair process for use with hybrid microcircuits having leaking seals.